Firmware updates are risky. Ensure the TP.MS338.PC821 board number exactly matches your hardware to avoid display issues or startup loops.

While holding the button, plug the TV back into the power outlet.

Use a high-quality USB 2.0 drive (8GB or 16GB is usually best). Format the drive to .

Press and on the TV panel (not the remote).

Once complete, the TV will usually restart automatically. during this process, as it can "brick" the motherboard.